Electric control system.



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HARRY WARD LEONARD, OF BRONXVILLE, NEW YORK.

ELECTRIC CONTROL SYSTEM.

Specication of Letters Patent.

Patented Nov. 5, 1912.

Application led October 2, 1909, Serial No. 520,669. Renewed September 9, 1912. Serial No. 719,445.

To all whom 'it may concern:

Be it known that I, HARRY WARD LEoN- aan, a citizen of the United States, residing at Bronxville, in the county of Vestchester and State of New York, have invented certain new and useful Improvements in Electric Control Systems, of which the following is a full, clear, and exact specification.

My invention relates to a system of electric control comprising the generation and utilization of electric energy and the control of apparatus so as to produce the desired change in its relationship.

My invention is particularly well ada )ted to the o )eration of electrically propelle vehicles wherein a )lurality of motors act upon a conunon load, ior example, as in a locomotive` or vehicles moving in water or air.

Amon the objects of my invention may he mentioned the reduction in first cost of the re uired apparatus, the obtainin of high eficiency under all conditions 'o operation, the securing of maximum torque during starting or during low speeds when ascending a grade or rounding curves, and securing high speed with reduced torque on a level. l also secure a smooth and gradual control of the speed and torque in an ellicient numner.

My invention also com )rises automatically moved electrically controllled switches for effecting the desired relationshi of the a paratus,and a master controller or contro llng the operation of such switches and other control of the apparatus.

Although my invention is capable of embodiment in various forms of apiaratus, I will describe one form thereof an( itl will be understood that various modifications may be made without departing from the scope of the invention.

ln the accompanying drawin s Figure 1 is a diagram il ustratln one orm of my invention, showing a p urality of electric generators, a plurality of propelling motors, a development of one form of drum controller. and other auxiliary apiaratus; and Fig. 2 is a diarram showing tie apparatus ap lied to a ve ticle.

eferring to Fig. 1, two direct current electric generators are shown having armatures 1, 1', and field windings 2, 2. The motors are indicated as of the direct current type havin armatures B, 3 and field windings 4, 4', tie motors being geared or otherwise related to the propel ing wheels of the locomotive so as to act in common upon the load. All of the apparatus indicated in the figure is carried upon the locomotive or vehicle to be propelled, or if desired may be carried partly upon one unit and partly upon another unit, comprising a train. The generators will be driven by any suitable means, such as by one or more gas engines E or other prime movers, or there may be a stationary source of electricity and current led upon the vehicle through suitable moving contacts and utilized to drive alternatlng or direct current motors located upon the vehicle, and which in turn drive the generator armatures 1, 1 preferably at substantially constant speed.

A self-exciting generator, or exciter, of the direct current type is indicated at 5, which supplies current to the field windin s 2, 2 of the Generators, and the field winings 4, 4 of t ie motors, and supplies, in this instance, the current for o eratin the electromagnetically controllo switc ies. This exciter may be mounted upon the shaft of either the generator 1 or generator 1, and thus driven by the same source of power as the generators, or the exciter may be driven by some auxiliary source preferably at substantially constant s eed. The development of the master contro ler C of the drum type is indicated at the right of Fig. 1, the fixed contacts or fingers being indicated on the vertical line (l, and when the controller is iu the ofl position, the Contact fingers being on the line 7, the motors will be entirelyidisconnected from the generators and no power will be transmitted to them. When the controller drum is turned so that the fixed contacts successively occu y various positions to the ri ht of the of position 7, the vehicle wil be driven in one direction, and when the controller is turned so that the fixed contacts successively occupy the various positions to the left of the oli position 7, the vehicle will be propelled in the reverse direction.

The resistances indicated at 8, connected between certain of the fixed contacts, are for the purpose of varying and controlling the current in the field winding 2 of the generator 1, and thereby vary and control the electromotive force generated thereby. The rcsistances indicated at 9, connected between certain of the fixed contacts, are ada ted to be inserted or removed successively tiiom the circuit of the field winding 2 of the other generator, and thereby control the eleetromotive force. In the circuit of the field windings 2 and 2 are indicated adjustablc. resistances 10 which may be varied by hand for Securing further control of the current in the generator field windings, and correspondingly vary the electromotive force of the generators, or these resistances may be adjusted for securing any desired adjustment of resistance of the field winding circuits so as to secure their proper relation to each other or to the remaining portion ot' the apparat-us.

At 11 are indicated resistances connected between certain of the fixed contacts and adapted to be inserted and witlulrmvn from the circuit of the field winding 4 of the motor 3, and similarly at 12 are indicated resistances connected between certain of the fixed contacts adapted to be inserted and withdrawn from the circuit of the field winding 4 of the. propelling motor 3. Adjustable resistances in the respective circuits of the field windings 4 and 4 are shown at 13, 13. which may be adjusted as desired for lsecuring additional control of the field strengt i of the motors, or for securing proper relationship between the motors so that cach will take its proper share of the load. and also for securing adjustment as required to the remaining portion of the apparatus.

lllectromagnetically o )erated switches 14, 14, having coils 15, 15 for acting u )on the iron cores of the switches and thereby raising them against gravity or other pressure, are shown for the purpose of closing a local circuit including the generator armat'ure 1 and the motor armature 3. The coils 15, 15 are shown connected in series with each other, and the circuit thereof leads to a pair of fixed contacts so that the current m the coils 15, 15 will be controlled by the operation of the master controller. A switch 16 of similar type to the switches 14, and having a closin coil 15, is shown for the purpose of closing the local circuit of the generator armature 1 and motor armature Il', the controllingr coil of switch 1G having leads connected to fixed contacts of the master controller. and having a resistance 17 in its circuit for limiting the current through the coil to the proper amount. At 18, 1f) are indicated two similar electromagnetic switches having controlling coils 15 for connecting both motor armatures in parallel to the circuit of the generator armature 1', and also in parallel upon the circuit of the two enerator armatures when they are connected in series with each other. The controlling coils of switches 18, 19 are connected in series with each other, and leads therefrom are connected to fixed contacts of the master controller. At 20, 21 are indicated similar electromagnetic switches having controlling coils 15, which switches are for the purpose of connecting the generator armatures 1, 1 in series with each other, as hereinafter explained. The coils of the switches 20, 21 are connected in series with each other, and have leads extending to fixed contacts of the master controller.

In considering thc particular embodiment. of my invention illustrated and described` it will be seen that the ampere capacity ot each generator and motor should preferably be the same, but the volt capacity of each generator need only be one-halt` that of the volt capacity of cach motor and the advantages of my invention in the form consi( ered are thus obtained with a kilowatt capacity of each generator only one-half that of each motor.

Considering now the sequence of operation secured by movement of the master controller in the form illustrated, it will be seen that when the master controller drum is moved from ofi' position, in which the fixed contacts are located on vertical lines 7, toward the initial starting position when the fixed contacts are upon line a, the fields of the two pro )elling motors are first energized from the exciter 5 by current passing rom the exciter to fixed contact 22 to the conducting strip on the controller drum on the line of this contact, thence in one path to the conducting portion on the drum and out through fixed contacts connected to the resistance 11, thence through the motor field winding 4 to another fixed contact, then to a conducting strip on the controller drum to the conducting strip on the drain opposite fixed contact 23, and then back to the other terminal of the exciter The field winding 4 of one motor will therefore be excited, and it will be seen by tracing the path of another circuit from the conductinr stri) opposite fixed contact 22 that the fiel( wintling 4 of the other motor will similarly be energized. It will be noted that initially the rcsistances 1l and 12 are connected in circuit but. these are fradnally cut out and the motor fields are fu ly excited when the drum is moved so that the same is in the starting position on line a. In this starting position the two switches 14, 14 and the switch 16 will be closed causing cach generator armature to be connected in a local circuit. with its respective motor armature. The closing of the switches 14 is secured by utilizn r current from the exciter 5 and the closed circuit of these coils may be traced from the exciter to contact 22, thence to the conducting strip on the drum of the master controller, thence by a connection to a conducting strip opposite contact 24, thence through the coils 15 of the switches 14 back to contact 25 to a conducting strip on the controller drum, and then by u connection to another condiictin strip on the drum to fixed contact 93, baer to the exciter. The closing of the switch 16 is similarly secured by current from the exciter 5, the circuit bein(T from contact 29. to a conducting strip on the drum. thence by a connection to a conducting strip opposite contact 26, and then through the coil 15 of the switch 16 hack to contact 27 to a conducting strip on the drum, and then by a connection to a conducting strip opposite contact 28 back toA the exciter. In this starting position the magnetic fields of the two generators will be low and cause the generator arnuitnre. to deliver a low electromotire force to the inotor armature for starting at u low speed. 'l`he low excitation of the generator fields is obtained by inserting the resistanccs 8 and f) in the field circuits of the generators, and in this instance the currcnt for exciting these fields is also derived from the exciter l'i.

'lhe patti of the current tliroii h the field winding Q from the exciter may traced as follows: from one tcruiiniil of the exciter 5 to fixed contact Q2 to a coiidiictiii strip on the controller drinn` and thence )y a connection to one of the upper segments on the drinn. out through contact 21) through the resistance 8 and field wiiidin 2 hack to contact 30, thence to a conducting strip on the drinn and by a connection to the strip opiosite contact Q3, and then to contact Q3 lack to the other terminal of the exciter. 'lhe circuit from the exciter through the field winding 2' of the other generator is from contact 22 through drnni connections to contact 31, then through resistance 0 and field winding 2' back to contact 82, and then through controller drum connections to fixed eontaet .23 back to the exciter. The maxinuiin ampere capacity of the generators and motors may be utilized in this position` or may be exceeded for a short length of time, if desired. giving large starting torque at low `speed. liy turning the controller successively through following positions on the drum. the sections of resistances 8 and 0 will he suewssively removed from the field circuits of the generators, thus gradually stm-ngthening their fields and causing a radually increased electromotive force to e generated by the generators and applied to the motors. This increase of electromotive force in the local power circuits will secure a gradual increase in speed without subjecting the vehicle or locomotive to nbriipt movements` and in position b all of the resistances 8 and t) will be removed from the field circuit of the generators` and they will then generate their maximum electroinotive force and secure corresponding speed of the vehicle. lt will he seen that tie resistance 8 is removed from circuit by following the current piith from the exciter through contact 22 and through drinn connections to the upper portion of an upper segment on the di'uin, out through contact 33 through the winding 2 to contact 30, and through drum connections to contact 23 back to the exciter. Similarly it will be seen that in this position b the resistance 9 is removed from circuit while the connections of the inotor fields and the coils of switches 14, 11 and 1G remain as previously explained, and any ot' the positions from a to I) may be used with advantage as ruiming positions.

'l`he positions following position b and to position '1' are transitory positions and for the. )urpose of securing a new relationship of tlie gncrator and armature circuits for securing further increase of s )eed and without interruption of the supp v of power to the vehicle. Movement to position c causes the closing of the switches 18 and 1t). the path of the current for exciting the coils of these switches being from the exciter to contact 22 through connections of the controller drum to contact 34, through the coils of the switches 18 and 1t) haelt to contact 35, and then through contacts on the controller drinn to contact Q3 back to the exciter. Other connections of position c renuiiii the sinne as in position I, aiid it will be seen that the closing of tht` switches 18. 1t) connects 95 the liiotor armature 8 in nirallel with tht` motor ui'iiiatiire ti' u )on tlie circuit of the generator aruiature 1 In position rl a ortion of the resistance 8 has been placed in the circuit of the field winding 2 so as to 10o wealteu the field strength of this generator to a sufficient degree to throw the load off of this generator and cause the generator urina` ture 1' to assume all of the load. When thtl controller assumes osition e, it will be 105 noted that the circuit through contacts 2-1,

Q5 has been broken, which causes the coils of switches 14, 14 to be deencrgized and these switches to be opened by gravity or other pressure. 'llie generator nrnuiture. 1 110 will therefore be disconnected from the crcuit of its motor, and in succeeding positions of control. the resistance 8 will lagradually inserted in the field circuit of the generator 1` causing its field to he grad- 115 ually weakened. and in position f this field will be entirely denergized by reason of the breaking of the field circuit at contacts 2u and 30.V When the controller assumes position g the switches 20. 9.1 will be closed due 120 to the energization of their controlling coils. the path of the current through these coils being from exciter 1', to contact. 22. through connections of the controller druni to contact '86. then through the coils of the 125 switches 20. 21 baclt to contact 37. then through connections of the controller drum to contact Q3 buck to the exciter. Movement of the controller to position It next causes the opening of the switch 13o lti by reason of the breaking of the circuit of its controlling coil atcontacts 26 and 27. In this position, therefore, it, will be. .seen that the generator armatures l, 1 have been placed in series with each other, and that the motor armatures are connected in parallel to each other in the circuit, as will be evident from tracing the path of the circuit from the upper terminal of armature ll in one path through switch 19, armature 2-1 and switch 1S, and through another path through armature 3 to a connection whicn leads to switch 21. then through `switch 21 nml generator armature l to switch Q0. ant. then b v a connection to the lower terminal of the generator armature l. It will tlms be seen that in this position /t the, generator armature I is generating its lt`ull electro motive force and has in series therewith the generator nrnutture 1. which is generating no electromotive force owing to tht` deinergizaticn of its field. In position i the field circuit of the generator 1 has been closed with all of the resistance 8 in series. and this generator will therefore generate a low electromotive force with the controller in this position. This generator arumture 1 being in series with the generator armature l. and the elect romotive force of the generator l being in such direction as to be additive to that of the other. the eleetromotive forte applied to the motors will be greater than that applied in position l) by the amount of eleetromotivc force generated by armature l. This condition. therefore` results in corresponding increase in speed of thc motors. urther movement of the coutrollcr through the intermediate positions to position causes the sections of the resistance 8 to be successively short-circuited giving a corresponding gradual increase in clcctromotive force generated b v the armature l. and correspondin ly increasing the clectromotive force applied to the motors. la position j the generator armature l will force which. added to the full eleetromotive force of the generator armature l. results in applying the lnaximum electromotive force to the motor arnutture giving corresptmdiug high speed.

Still further increase in speed is obtained by passing to position 1.-. which results in successively inserting sections of the resistunces ll and l. in the fleld circuits of the motors and dne to this weakening of the motor field strengths. the motors will graduallv attain then' maximum speed.

vMovement of the controller backward from position /tf to ofi' position will cause tbc various connections above described to take place in reverse order, and result in gradually bringing the movin load element to rest. It will be noted tiat when the motor field circuits are finally broken, the arrangement of the contacts is such that the resistances 1l and 12 are inserted in the circuits and colx'espomlingly reduce the current; and minimize sparking at the final break. A1so,whenever the field circuits of the generators are finally broken, the full resistances 8 and 9 are connected therein.

In order to reverse the direction of rotation of the motors, and thereby reverse the movement. of the vehicle or locomotive, the direction of current in the field circuit of the motors may be reversed, or the direction of the current. through the moto armatures, but I prefer to reverse. the direction of current. through the field windings of the generators, and thereby reverse the direction of electromotive force enerated by the generator armatures whici reverses tic direction of the current apilied to the motor armatures. This reversa of the enerator fields may be secured by any suita le form of switch, but I prefer to arrange the master controller so that movement tliereof in the reverse direction from ofi' position will cause the reverse. movement of the vehicle by cansing the reversal of the generator fields. I also prefer to arrange the master controller vso that reverse movement from ofi' position will cause the same connections as already described.

Thus, referring to the drawings, it will he noted that. when the controller is moved from ofi' position so that the fixed contacts malte engagementl upon line (1.', th'e connections are the same as made in position n, excepting that the direction of cttrrent through the generator field windings is the reverse of that obtained in position n., as may readily be seen by tracing the connections from the exciter 5 through the generator field windings. The subsequent coanections obtained by the master controller bv movement from posit-ion a', to final position l." are the same as already described with reference to positions a. to le, excepting that the direction of the current through the generator field windings is such ns to maintain the reversed condition. Thus the controller is arranged to obtain all changes of speed up to the maximum for both the forward and reverse movement of the vehicle or locomotive.

It. will be understood that the resistances 8. tl, 11 and l2 may be arranged to have any desired number of sections which will be successively inserted and removed from the field circuits, and also that various other modifications may be mudo to suit the retuirements ot the desired operating con t itons.

I'Iavin thus described my invention, I declare t iat what I claim as new and desire to secure by Letters Patent, is-

1. The combination of a plurality of electric motors working upon a common load, a plurality of generative windings, means for connecting the generative windings to windings of said motors for supplying eurrent to windings of said rmotors for securing ceitaiii speed, said generative windings supplying currents independently of each other to tie motor windings, and for connecting the generative windings in series with each other to su ply the motor windings for obtaining a hig ier speed.

2. The combination of a plurality of sources of electromotive force, a plurality of electric motors working upon a common load, and controlling means for connecting said sources in local indcpent'lent. circuits with said motors, for gradually increasing tho electromotire force of said sources, for connecting said sources in series with cach other for supplying energy to the motors, and for gradually increasing the joint electroinotive force of said sources.

3. The combination of a plurality of sources of electromotive force, a pluiality of electric motors working upon a common load, and a single controllinlg means for connecting said sources in loca independent circuits with said motors, for gradtially in creasing the eleetromotive force of said sources, for connecting laid sources in series with each other for su pl 'ing energy to the motors. and for grailinilly increasing the electroniotive force of said sources.

4. 'Ihe uietliorl of controlling the sieed of a plurality ot electric motors wor ting u )on a common load, which consists in supp ving energy to corresponding windings of the motois from sources of electromotive force independently of each other increase ing the electromotive force of sait sources, and connecting said sources in series with each other for increasing the electroinotive force applied to the said motor windings.

The combination of a plurality of sources of eleetromotive force, a pluralitv of motors working upon a common load automatic switches or connecting said sources to said motors in independent circuits respectively and for coniiectin said sources in series with each other for jointly supilyinY the motors, and a master control er or controlling said switches and for causin the electroinotivo force of said sources to )c varied.

G. The combination of a plurality of sources of electremotive force, a plurality of motors working uioii a common load, automatic switches for connecting said sources to said motors in independent circuits respectiveltY and for connecting said sources in series with each other for Jointly supilying the motors, and a master controller for controlling said switches, for causing the electromotive force of said sources to be varied, and for varying the field strengthsl of the motors.

T. The combination of :i plurality of sources of electric energy for moving a coinuioii load. means for varying the division of the total energy between tlie sources and the relative circuit connections, said means comprising u plurality of automatically movable circuit controlling elements and :i controller therefor.

8. A plurality of generators, a plurality of motors worting upon a common load, each of said generators and of Said motors having a tiel( winding adapted to be separately excited, a common exciter for said field windings, and connections for causing euch of said generators to suiply ener y to its respective motor indepent ently of t io other of said enerators.

D. 'Ilie com iination of a plurality ot sources of electromotive force, a pluralityI of motors working upon a common load, automatic switches for connecting said sources in series with each other for jointly supilving the motors, and a master control ei for controllingr said switches and for causing the elewtroinotive force of said sources to be varied.

10. The combination of a plurality of sources of electromotive force, a pluralit of motors working uion a common loatll automatic switches ior coniiectin said sources in series with each other for )ointly sup I vin the motors, and a master control er fiir controlling said switches, for causing the electromotive force of said sources to be varied, and for varying tho ield strengths of the motors.

In testimony whereof I alix my signature, in presence of two witnesses.

ll. WARD LEONARD. Wi t nesses BUniti-i S'ross,

Gizoaas Kavasoon.

Ooptel of this patent may be obtained for ave oentl auch, by nddreutng the Commissioner of Patents, Washington. D. O.

[t ie hereby certified thnt in Letters Patent No. 1,043,778, granted November 6, 1912, upon the application of Harry Werd Leonard, of Bronxville, New York,

for un improvement in Electric Control Systems, an error appears in the printed specification requiring correction es follows: Page 4, line 45, after the word will insert the words ba producing ita maimum electromotive; and thnt the said Letters Patent should he reed with this correction therein that the enme muy conform to the record of the case in the Patent Oiice.

Signed and sealed this 17th day of December, A'. D., -1912.

[en/ln] C. C. BILLINGS,

Acting Commissioner of Patents. 

